Increasing the precision of intramedullary nailing in femoral derotation osteotomies by larger core locking bolts. A biomechanical study

IF 1.4 3区医学 Q4 ENGINEERING, BIOMEDICAL

Clinical Biomechanics Pub Date : 2025-02-04 DOI:10.1016/j.clinbiomech.2025.106449

Anders Grønseth , Jan Egil Brattgjerd , Joachim Horn

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引用次数: 0

Abstract

Background

To correct increased femoral anteversion, surgeons perform femoral derotational osteotomies in symptomatic adolescents. Using an intramedullary nail as fixation in this setting, undersized locking screws reduce rotational precision by allowing nail toggling. However, the extent to which better-fitting locking bolts improve rotational precision in femoral derotational osteotomies remains unclear. Accordingly, we tested the hypothesis that adequately sized locking bolts enhance rotational stiffness and limit displacement, thereby decreasing nail toggling in femoral derotational osteotomies in vitro.

Methods

We evaluated rotational stiffness, angular displacement, and laxity at zero-loading in 12 synthetic femurs with a transverse gap osteotomy to the shaft. After inserting a pediatric intramedullary nail, femurs were fixed with either conventional 4.5 mm locking screws or locking bolts with a 0.3 mm larger core diameter. Non-destructive quasi-static rotational testing of 4 Nm external and internal torque was performed according to a predefined protocol.

Findings

We found significantly higher mean rotational stiffness with locking bolts than with locking screws, demonstrating a 150 % increase (0.4 Nm/degree vs. 1.0 Nm/degree, P < 0.001). Mean angular displacement was significantly lower with locking bolts than with locking screws, exhibiting a 61 % decrease (21.9 vs. 8.6 degrees, P < 0.001). Additionally, laxity with locking bolts was 69 % lower than with locking screws (3.2 degrees vs. 10.4 degrees, P = 0.0027).

Interpretation

Locking bolts with a larger core diameter enhances rotational stability and fixation precision, making them a valuable advancement in intramedullary nailing for femoral derotational osteotomies. These findings may also have implications for fracture treatment.

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来源期刊

Clinical Biomechanics 医学-工程：生物医学

CiteScore

3.30

自引率

5.60%

发文量

189

审稿时长

12.3 weeks

期刊介绍： Clinical Biomechanics is an international multidisciplinary journal of biomechanics with a focus on medical and clinical applications of new knowledge in the field. The science of biomechanics helps explain the causes of cell, tissue, organ and body system disorders, and supports clinicians in the diagnosis, prognosis and evaluation of treatment methods and technologies. Clinical Biomechanics aims to strengthen the links between laboratory and clinic by publishing cutting-edge biomechanics research which helps to explain the causes of injury and disease, and which provides evidence contributing to improved clinical management. A rigorous peer review system is employed and every attempt is made to process and publish top-quality papers promptly. Clinical Biomechanics explores all facets of body system, organ, tissue and cell biomechanics, with an emphasis on medical and clinical applications of the basic science aspects. The role of basic science is therefore recognized in a medical or clinical context. The readership of the journal closely reflects its multi-disciplinary contents, being a balance of scientists, engineers and clinicians. The contents are in the form of research papers, brief reports, review papers and correspondence, whilst special interest issues and supplements are published from time to time. Disciplines covered include biomechanics and mechanobiology at all scales, bioengineering and use of tissue engineering and biomaterials for clinical applications, biophysics, as well as biomechanical aspects of medical robotics, ergonomics, physical and occupational therapeutics and rehabilitation.